Investigating officer inspector Vilas Pawar, attached to Khar police station, informed that thr cylinder must have leaked gas, which seeped into the nearby cupboard. Thes gas expanded due to heat, and was ignited dut to poor ventilation and contact with some flameable substance, Pawar added.

At first, the police theorised that the blast could have been caused by explosives, since the gas cylinder was intact even after the blast. But this theory was dismissed late in the afternoon after the ballastic department joined the inquiry on what caused the disaster.

``The condition of the Kulkarnis admitted at Bhabha is stable, and they are presently not in a state of shock,'' said Dr Deepak Sharma, who was on duty.

The Kharpolice added Fire Brigade officials have taken charge of the gas cylinder and the hose for inquiry. A report is awaited.

An eyewitness said he heard a loud noise around 7.15 am in the morning. At first he thought it was crackers, but he soon heard the rumbling of the collapsing walls.

The explosion had ripped open the rear side of the ground floor tenement. Household items lay strewn all over the backyard, which was later sealed off by the police.

Residents from the neighbourhood in Pyari Nagar

The illfated house was owned by one R Mahadik and it was rented out to Ramakant Kulkarni, barely a hundred meters from the beachfront. Fortunately, Ramakant was out of the house at the time of the explosion.